Shop Windows to the Universe

What’s in a global climate model? The Community Climate System Model (CCSM version 3) that is run with the supercomputer at the National Center for Atmospheric Research incorporates data about all of the natural processes shown in this diagram to simulate Earth’s complex climate system.
Click on image for full size UCAR

Related links:

What Is a Climate Model?

Global climate models (GCMs) use math - alot of math - to describe how the atmosphere, the oceans, the land, living things, ice, and energy from the Sun affect each other and Earth's climate. Thousands of climate researchers use global climate models to better understand how global changes such as increasing greenhouses gases or decreasing Arctic sea ice will affect the Earth. The models are used to look hundreds of years into the future, so that we can predict how our planet’s climate will likely change.

There are various types of climate models. Some focus on certain things that affect climate such as the atmosphere or the oceans. Models that look at few variables of the climate system may be simple enough to run on a personal computer. Other models take into account many factors of the atmosphere, biosphere, geosphere, hydrosphere, and cryosphere to model the entire Earth system. They take into account the interactions and feedbacks between these different parts of the planet. Earth is a complex place and so many of these models are very complex too. They include so many math calculations that they must be run on supercomputers, which can do the calculations quickly. All climate models must make some assumptions about how the Earth works, but in general, the more complex a model, the more factors it takes into account, and the fewer assumptions it makes. At the National Center for Atmospheric Research (NCAR), researchers work with complex models of the Earth's climate system. Their Community Climate System Model is so complex that it requires about three trillion math calculations to simulate a single day on planet Earth. It can take thousands of hours for the supercomputer to run the model. The model output, typically many gigabytes large, is analyzed by researchers and compared with other model results and with observations and measurement data.

You might also be interested in:

Frozen water is found in many different places on Earth. Snow blankets the ground at mid and high latitudes during winter. Sea ice and icebergs float in the chilly waters of polar oceans. Ice shelves fringe...more

Even though only a tiny amount of the gases in Earth’s atmosphere are greenhouse gases, they have a huge effect on climate. There are several different types of greenhouse gases. The major ones are carbon...more

The sea ice that floats on the Arctic Ocean is covered with snow all winter. The snow-covered ice is bright white so it absorbs very little of the solar energy that gets to it. And during the Arctic winter,...more

The climate where you live is called regional climate. It is the average weather in a place over more than thirty years. To describe the regional climate of a place, people often tell what the temperatures...more

Earth’s climate is warming. During the 20th Century Earth’s average temperature rose 0.6° Celsius (1.1°F). Scientists are finding that the change in temperature has been causing other aspects of our planet...more

Global climate models are used to predict what will happen to Earth’s climate in the future. Groups like the Intergovernmental Panel on Climate Change (the IPCC) compare the results from several different...more

In the last decades, computers have become a normal part of life. They are used to send e-mail, write a school report or look up recipes. They are used to keep track of the balance in your bank account....more